Faria Coral 2" Cylinder Head Temperature Gauge (60-120 F) w/Sender [13009]Coral 2" Cylinder Head Temperature Gauge (60 120 F) with Sender Perimeter lighted Black dial with stylish White and Blue graphics, Black aluminum bezel with burnished leading edge, contoured White pointer, and flat glass lens. A temperature gauge operates by sending a low amperage current through the gauge's meter to the ground via a sending unit with variable resistance. The resistance of the sending units increases or decreases with the changes in